Film actuating mechanism



'June 5, 1945. 0, c v HAL 2,377,756

FILM ACTUATING MECHANISM Original Filed Jan. 9'. 1940 IN VEN TQRS.

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I normeoncaivininansas Git-y, M6), williamGi ,Wils.on,', Merriam, Kans and; Thomas; R2. v Smith, Newton,,-Iowa, assignors to; MnvieMite A 'Cbrporatibn Kansas City-,, Mo.-,, a corppration of Missouri.

Original application January-'9', I940; SprialNo.v 313,088. Divided and this applicatibmOctbben 13, 1942, Serial No. 461,838r i 1 Claim. (01. 271-23) The present invention relates to motion picture apparatus and more particularly to a film actuating mechanism for a motion picture projector. The film path through this projector is so arranged that the film passes over a minimum number of controlling members such as sprockets, rollers, etc. This makes possible very quick and simple threading of the film through the apparatus, and the rolls that support the film around the sprocket are so constructed and arranged that the spring of the film tends to hold it onto the sprocket.

comprehends other details, arrangements of parts, features and constructions without departing from the spirit of the invention.

In the drawing:

Figure 1 is a view in side elevation of a motion picture apparatus employing the novel construction.

Figure 2 is a view in rear elevation of the sprocket and guard or retainer for the film.

Figure 3 is a fragmentary enlarged view in vertical cross section taken on the line 3--3 of ment with the sprocket teeth and includes a leafspring mounted against the toothed end of the sprocket. On the spring are fixed suitably shaped piecesor guard blocks which project over the surface of the film between the sprocket also acts as a lateral guide for the film in threading the apparatus or projector and prevents the film from being pushed past the sprocket by an returns to its original position holding the piece or block over the film edge and thereby preventing the film from rising up or climbing off the sprocket teeth. The present application is adivision of our co-pending application Serial No. 313,088, filed January 9, 1940.

The present invention further comprehends a novel actuating mechanism including a single sprocket having multiple functions, the top surface of the sprocket functioning as a pull down and feed sprocket, and the bottom surface functioning as the sound sprocket in that it pulls the film past the sound aperture as the take-up sprocket, and as the hold-back sprocket.

Further objects are to provide a construction of maximum simplicity, efficiency, economy and ease of assembly and operation, and such further objects, advantages and capabilities as will later .more fully appear and are inherently possessed holes and the edge of the film. The 'leaf spring Figure 1.

Referring more particularly to the construc tion disclosed in the drawing, the novel illus trative embodiment disclosed comprises a support or mounting plate I upon which is suitably mounted the projecting apparatus. In the forward part of this support is adjustably mounted a lens 2 in a lens mount 3. The film 4 is fed from the feed roll (not shown) over the roller 5 and thence over a sprocket 6 and between guide rollers I and 8 to the picture aperture located Within the enclosure 9. From the picture aperture the film travels over a sound drum housed within the enclosure Ill and is held against a sound drum by means of a pad roller H. As it leaves the sound drum, the film is guided over a roller I2 and is passed over a guide roller I3. From there it is passed over the bottom surface of the sprocketB and guide roller l4.

--In order to holdthe film 4 onto the top and bottom of the sprocket 6, the invention comprehends a sprocket retainer I5. The guide rollers 5, 1 and 8 and the guide rollers I3 and I4 are so disposed and arranged that the natural tendency of the film to straighten out from the bends imposed thereon keeps the film on the sprocket. This sprocket retainer or guard l5 comprises a leaf spring 16 mounted behind the sprocket and secured toa bearing or hub ll for the shaft S by screws or other suitable means 18. Suitable blocks or projecting pieces I9 are fixed to the leaf spring at its opposite ends by means of suitable attaching means such as rivets, solder and the like, so as to project out over the surface of the film from the edge into the sprocket holes.

In the operationof the projector, the film 4 l is fed from the feed roll over the roller 5 and thence over the sprocket and between guide rollers 1 and 8 to the projecting apparatus. The film travels in such a path as to require a mini mum number of supporting parts or rollers, and these parts or rollers are so placed as to make the film path of such shape that the film will not be subjected to sharp bends or mis-handling.

The film is threaded onto the upper surface of the sprocket B by bending the spring I6 backwards and therebypermit the film to slip down over the sprocket teeth past the blocks or projections IS. The spring then returns to its original position, returning the blocks or guards I!) to their operative position over the edge of the film to thereby overcome any tendency of the film to rise up or climb ofi the sprocket teeth. Similarly, the projecting guard or block 19 located below the sprocket 6 functions to retain the film 4 onto the sprocket teeth as the film passes from the guide roller I3 to the guide roller [4. From the guide roller I 4 the film passes over a snubber roller 20 mounted upon a spring control arm 21, and from there this film passes onto a take-up reel (not shown).

Having thus disclosed the invention, we claim:

In a sound motion picture projector, a sprocket for feeding film to and withdrawing it from the projector, and means for holding the film upon the teeth on the upper and lower side of the sprocket and consisting of a leaf spring positioned adjacent the sprocket with a projection on the upper and lower end of the leaf spring extending over anedge of the film as it is fed to and returned from the projector to maintain the film upon the teeth of the sprocket and form a lateral guide for the film thereat, either end of the leaf spring being adapted to be withdrawn to move its projection away from the sprocket to permit the film to be threaded onto its upper or lower side.

FORREST O. CALVIN.

' WILLIAM G. WILSON.

THOMAS R. SMITH. 

